But the production that launched Thursday at Lyric Opera of Chicago – the first opening night since the musicians’ strike that ended Sunday – proved that “Idomeneo” can appeal to modern-day sensibilities. For though some seats emptied by the time the third (and final) act began, a majority of the audience stayed, for several good reasons: superb singing, astute acting and, above all, one of Mozart’s most imposing operatic scores.

Yes, “Idomeneo” requires considerable suspension of disbelief, for its tale of King Idomeneo could make even the most credulous listener balk. After striking a rather unfortunate deal with the god Neptune – in order to save himself from turbulent seas – Idomeneo learns he’s required to kill the son he hasn’t seen for years. The two don’t recognize each other when they meet and take quite a while to realize the predicament they’re in. Idomeneo’s subsequent attempts to evade his promise to Neptune causes all manner of catastrophe and death. His son, Idamente, heroically slays a vicious monster along the way, then offers himself up to his father’s sword. A love triangle also ensues. And so forth.

What matters most here, however, are not the machinations of a creaky narrative but its underlying emotional currents and Mozart’s sometimes magisterial, frequently tender ways of expressing them. Combine the themes of filial love and tragic desperation with Mozart’s sublime writing for vocal solo, duet, trio, quartet and chorus, and you have a power far greater than the inherent weaknesses of the story.

So when the prisoner Ilia, sung by soprano Janai Brugger, early on laments the deaths of her family members at the hands of Idomeneo’s forces, we are instantly moved by the profound lyricism of Mozart’s writing in “Padre, germani, addio!” All the more in Brugger’s rendition, the warmth of her tone matched by the ardor of her delivery.

Before long, Idamente – who instantly finds himself as smitten with Ilia as she is with him – pleads that Ilia’s sorrows are not his fault in “Non ho colpa.” Once again, high-flown melody conquers all, with mezzo-soprano Angela Brower making her Lyric debut as a remarkably intense Idamente (in Mozart’s time, a castrato played this part). Brower elegantly finessed the virtuoso vocal lines for which castrati were celebrated, but she also shaped them to compelling effect. Better still, the romantic charge between Ilia and Idamente was unmistakable from the start, not only because of the way they regarded each other physically but because of the very quality of their instruments, Brugger’s rounded, dusky timbre answered by Brower’s bright and radiant tone.

Much of the weight of the drama naturally falls on Idomeneo, who’s psychologically tortured by his oath to kill the character who turns out to be his son. Tenor Matthew Polenzani created a brooding, deeply troubled Idomeneo, the pathos of his situation expressed by the gloom in his face and more than once by the catch in his throat.

Every opera on this epic scale requires a villain, and this production has a fine one in soprano Erin Wall’s Elettra. The narcissistic self-obsession Wall conveyed in “Estinto e Idomeneo” morphed into delicious self-delusion in “Idol mio, se ritroso” and blossomed into full-blown insanity with “Oh smania! oh furie!” and Elettra’s culminating “D’Oreste, d’Aiace.” Still, the quivering hands were a bit much.

Vocally, the highlights of “Idomeneo” remain the ensemble pieces, which came off extraordinarily well. One admired the deliberate tempo and hushed intimacy that music director Andrew Davis established for the second act trio, “Pria di partir, oh Dio!” To hear Polenzani, Wall and Brower sustain seemingly endless lyric lines at a relatively hushed dynamic level in this enormous house was to experience one of the most sublime moments of the evening. Another came with the third act quartet, “Andro ramingo e solo,” the three aforementioned singers plus Brugger intertwining their phrases while emphasizing music, not pyrotechnics.

The chorus emerges as practically a character unto itself in “Idomeneo,” and Lyric’s ensemble sounded sumptuous but well within Mozartean style (plaudits to chorus master Michael Black). Yet many of the chorus’ gestures – in this re-staging of Jean-Pierre Ponnelle’s 1982 production, with David Kneuss making his Lyric debut as revival director – were exaggerated nearly to the point of melodrama, alas.

In the end, though, the luster of this cast’s singing and the gravity of its characterizations made this an “Idomeneo” that speaks lucidly to our time.